How do I modify the stream from a USB camera via a kernel level filter driver (or is there a better way)

kyasui 1

I'm looking to write a filter driver that can modify the video stream from USB camera class devices, for instance putting a watermark on it, and seeing it modified on any other application like skype or camera app.

However I've been reading the documentation available online, and I'm not finding what i need. For instance I see how theres kernel streaming in DirectShow's "How Hardware Devices Participate in the Filter Graph" but this isn't expanded on. I've learned how to write a kernel level filter driver like Chew Esmero's "ccfltr" but this simply copies the data to a shared memory available to userland.

Could someone kindly point me in the right direction to achieve this? Thank you very much.

In terms of development environment, I have a target device and kernel debugging setup via WinDbg, using Visual studio 2019, Windows 10 SDK (10.0.19041.0) and corresponding WDK.

柱江郭 0 Reputation points

2023-08-18T07:11:26.6933333+00:00

I am doing the same thing, did you solve it please?

1 answer

MichaelXu-MSFT 1 Reputation point

2020-08-31T08:07:02.323+00:00

In this scenario, you need to customize the USB camera driver and replace the built-in driver. You may refer to this graphics driver samples.
Adding watermark to video stream need you analysis the video frame and mix the watermark to the frame, generally, you need to use a third party for that. It is not easy to do that. We recommend you to add the watermark in application. There are many libraries can do that.
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kyasui 1 Reputation point

2020-09-03T22:09:09.667+00:00

So as I see mentioned in https://github.com/microsoft/graphics-driver-samples/issues/53 it seems the samples you linked are for graphics rendering, and I'm not sure if that is related to the camera stream.

I found this instead https://github.com/microsoft/Windows-driver-samples/tree/master/avstream/sampledevicemft

Which apparently showcases a DMFT, but the solution builds just a dll, and the required apps and driver examples seem to have been depreciated and removed. Do you know if there is a supported alternative that functions like this?

Thank you for your time.

MichaelXu-MSFT 1 Reputation point

2020-09-04T08:05:21.48+00:00

Were you developing on Windows IoT Core or Windows IoT Enterprise? If on Windows IoT Enterprise, you can refer to the Watermark Sample in DirectShow samples which are included with the Windows SDK. This sample blends a static bitmap onto a video during playback. Microsoft had not added directshow support to Windows IoT core yet.

kyasui 1 Reputation point

2020-09-04T13:55:11.727+00:00

Thank you for responding, I was previously looking for those samples. I'm using the most recent windows SDKs but i did not see iDirectShow samples in my sdk, so im guessing i have the former. Is it possible to see the VMR-9 example somewhere online?
I see this: https://github.com/microsoft/Windows-classic-samples/tree/master/Samples/Win7Samples/multimedia/directshow/vmr9
for Windows 7, but im worried if these tools are depreciated

kyasui 1 Reputation point

2020-09-04T15:05:51.727+00:00

Another thing is these samples are manipulating video files. Is this relevant to accessing and modifying the camera stream buffer?

MichaelXu-MSFT 1 Reputation point

2020-09-07T09:39:07.3+00:00

This is not relevant to accessing camera stream buffer, but relevant to modifying the video stream from camera?Before modifying the video stream buffer, you can find a way to capeture the usb camera stream. Please refer to this document(https://video2.skills-academy.com/en-us/windows/win32/directshow/about-video-capture-devices).
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How do I modify the stream from a USB camera via a kernel level filter driver (or is there a better way)

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